1. Field
This invention pertains to containers used for the sterilization of dental and medical implements. It specifically provides a container which effects a Morton-type closure, and provides for viewing of the contents of the container without disturbing the closure.
2. State of the Art
Dental and medical implements have generally been sterilized by enclosing them within a rigid covered container, and then exposing the container and its contents to sterilizing conditions. In some instances, the container is provided with openings to permit circulation of chemical vapors, heated air, or steam over the implements within the container. Heretofore, these containers have not permitted the viewing of the contents of the container without subjecting them to nonsterile conditions. Neither have those containers which permit circulation of vapors through the interior been capable of maintaining a sterile environment within the container after its removal from a sterilizer. Typical of conventional containers used with clinical, medical and dental sterilizers are those commonly referred to as "Swedish" trays.
In the field of microbiology, it is often desirable to purge the nonsterile or otherwise undesirable atmosphere from a vial or similar container, replacing it with a biologically inert atmosphere such as nitrogen. Once the desired atmosphere is present in the vial, it is necessary to maintain it during a period of storage. There has evolved a class of closing structures, often embodied as covers or caps, for use with vials or other containers in microbiological procedures. Such structures are known as "Morton" closures. When a Morton-type closure is implaced upon a vial, for example, and the vial is placed in contact with a dynamic source of desired gas (e.g. nitrogen), the desired gas flows through the closure to circulate through the vial, thereby displacing the initial atmosphere from the vial. When the vial is stored in a static ambient atmosphere, the closure serves as an effective barrier against penetration of the ambient atmosphere into the vial. Within the context of this disclosure, the essential characteristics of a Morton-type closure include: (1) suitable access through the closure into and out of the interior of a container to permit the displacement of the initial atmosphere by a desired atmosphere provided to the vicinity of the closure under dynamic flow conditions and (2) sufficient structural protection for that access to contain the desired atmosphere within the container and function as a barrier against penetration by an undesirable ambient atmosphere through the closure under static storage conditions. For example, the closure may consist of an aperture through the vertical sidewall of a container with a physical barrier across the top and spaced slightly in front of the aperture to permit a travel path of vapors in an upward or downward direction with respect to the structure either before or after passing essentially horizontally through the aperture.
Various transparent sheet materials are known to the art. These materials may be provided in flexible form so that they may be conformed to cover objects of varying shapes and sizes. Certain transparent sheet materials are provided in very thin sheets known as films. These films may range from as little as one to a few mils thick. Certain well-known transparent films are marketed under the tradename NYLON. One example of a heat-pervious thermoplastic transparent sheet material is marketed under the tradename designation M&Q Grade 6/6 HS Nylon Flat Sheet by M&Q Plastic Products of Freehold, N.J. Heat-pervious films of this type are impervious to vapors and airborne microorganisms at normal room temperatures, but upon heating become pervious to sterilizing vapors. They are refractory to sterilizing conditions.